#ifndef __SIGMA_FINCTION_H_
#define __SIGMA_FINCTION_H_

#include "std_def.h"
#include "neuron_calc.h"

class sigma_function : public neuron_calc
  {
public:
   sigma_function();
   virtual ~sigma_function();

   virtual double calc(double in, double p1);
   virtual double calc_back(double in, double p1);

  protected:
   double atanh(const double & v);
  };

#endif //__SIGMA_FINCTION_H_
